ROS-mediated Cytotoxicity and Macrophage Activation Induced by TiO2 Nanoparticles with Different in vitro Non-Cellular Photocatalytic Activities

Abstract

AIM: The aim of the study described in the present paper was to assess several in vitro effects of TiO2 nanoparticles with different colloidal and photocatalytic properties on RAW 264.7 macrophages.METHODS: The cells were exposed to Degussa P25 titania and two other types of nanoparticles synthesized by a hydrothermal procedure in our laboratory: undoped and Fe3+-doped TiO2. Compared to Degussa P25, the hydrothermal nanomaterials were significantly less active in inducing cytotoxicity, production of intracellular reactive oxygen species (ROS) and release of pro-inflammatory cytokine interleukin-6 (IL-6). The induced effects were analysed with respect to nanoparticle size, surface charge, hydrophilicity, semiconductor bandgap energy and photocatalytic generation of ROS under non-cellular conditions.RESULTS: The overall results indicated that TiO2 nanoparticles with higher surface charge, hydrophilic surfaces and enhanced photocatalytic properties may preferentially induce macrophage cell damage and inflammation compared to other TiO2 nanomaterials.CONCLUSION: The present findings are relevant for studies regarding the evaluation of risks raised by self-cleaning technologies involving nanosized hydrophilic TiO2 photocatalysts as well as development of synthesis methods optimized for producing biocompatible TiO2 nanomaterials.